Well, that's a good indication... This number is the date of the executable, expressed in seconds since 1970-01-01 00:00:00. Your executable has a time stamp around November 22, 2015... My timestamp is May 10, 2017, much more compatible with a recent Gimp version. Two things to do:
* Find that directory (C:\Program Files\GIMP 2\lib\gimp\2.0\plug-ins, likely) and check the file dates. In mine no file is older than May 10, 2017. My file-tiff-load.exe is 67,328 bytes.
* If there are too many older files, uninstall Gimp, erase C:\Program Files\GIMP 2\ if it remains (any plugins left?) and reinstall. and check the timestamps again....
* Find that directory (C:\Program Files\GIMP 2\lib\gimp\2.0\plug-ins, likely) and check the file dates. In mine no file is older than May 10, 2017. My file-tiff-load.exe is 67,328 bytes.
* If there are too many older files, uninstall Gimp, erase C:\Program Files\GIMP 2\ if it remains (any plugins left?) and reinstall. and check the timestamps again....